This invention pertains to an improved, hydraulically actuated coupler for an industrial, agricultural, or earth-moving vehicle, such as a skid-steer loader, in which the coupler serves to couple an implement to the vehicle and to uncouple the implement from the vehicle.
The implement may be a dirt bucket, a grain bucket, a manure fork, or any other implement for such a vehicle. If the vehicle is a skid-steer loader having lifting arms and tilting cylinders, the coupler can serve to couple the implement to such arms and cylinders and to uncouple the implement therefrom.
Prior couplers are known in which vertically movable, spring-loaded pins are wedged into orifices in an implement so as to couple the implement to such a vehicle. The pins may be withdrawn so as to uncouple the implement. See, e.g., Bauer et al. U.S. Pat. No. 3,672,521 and Cochran et al. U.S. Pat. No. 4,545,720. A disadvantage of those couplers is that, unless the pins are protected so as to prevent their lower ends from striking rocks or other obstacles while the vehicle is operating, the pins can be dislodged inadvertently, whereby the implement can be uncoupled inadvertently.
Prior couplers also are known in which hydraulically actuated pins, or clamps, are employed, which are actuated by hydraulically actuated piston-cylinder mechanisms. See, e.g., Lane U.S. Pat. No. 3,204,793, Wallberg U.S. Pat. No. 3,269,570, and Steelfab British Patent Specification No. 975,029. See, also, Uchida U.S. Pat. No. 4,116,347 and Frisbee U.S. Pat. No. 4,583,906. It is suggested in Wallberg U.S. Pat. No. 3,269,570, column 2, lines 66 and following, that such piston-cylinder mechanisms may be connected to a hydraulic system used for hydraulic control of lifting levers of a loading truck.
One mode of conceivable failure of such a coupler employing hydraulically actuated pins, as actuated by such piston-cylinder mechanisms connected so as to receive hydraulic fluid from a hydraulic system having another function, e.g., to lift a load, is that reverse flow of hydraulic fluid from the piston-cylinder mechanisms actuating the pins may be possible when the hydraulic system is delivering hydraulic fluid for another function, as it then may be possible for hydraulic fluid from the piston and cylinder mechanisms to flow with hydraulic fluid being delivered by the hydraulic system. Thus, if the pins are dislodged inadvertently when reverse flow is possible, the implement can be uncoupled inadvertently.
There has been a need, to which this invention is addressed, for an improved, hydraulically actuated coupler for an industrial, agricultural, or earth-moving vehicle, such as a skid-steer loader.
Hereinbefore, and hereinafter, directional terms such as "front", "back", "frontwardly", "backwardly", "upper", and "lower" are used merely for convenient reference to relative positions of different parts and to relative directions and are not intended as limiting.